IME, TUIs provide constraints to the application that help them focus on their tasks without other distractions. TUIs are typically very responsive- you issue

IME, TUIs provide constraints to the application that help them focus on their tasks without other distractions. TUIs are typically very responsive- you issue a command, and there's no wait. Feedback is nearly instantaneous. There are GUI apps that share this characteristic, if their authors put latency concerns as one of their primary goals, but the majority do not. Even fractions of seconds are noticeable, and make a significant impact on the usability of an application. TUIs are keyboard driven, so I don't have to reach for a mouse for most operations, which slows down most operations, and can promote RSIs. GUIs do often have keyboard shortcuts, but they still suffer from higher latency, and generally aren't a high priority concern for the UI author, so the shortcuts tend to be inconsistent, and not usually customizable, and users typically cannot create their own.